Apparatus for sorting timber



Oct. 8, 1963 R. 1.. AITKEN 3,

. APPARATUS FOR SORTING TIMBER Filed April 15, 1961 v 4 Sheets-Sheet 1 ROBERT LOUDON Al T/(EN 1963 R. 1.. AITKEN 3,106,292

APPARATUS FOR SORTING TIMBER Filed April 13, 1961 4 Sheets-Sheet 2 RUBERT LOUDON AIKEN Oct. 8, 1963 R. 1.. AlTKEN ,1

- APPARATUS FOR SORTING TIMBER 1' Filed April '13, 1961 '4 Sheets-Sheet S l/WE/VTOK ROBER LOUDON AIKEN ATTORNEY Oct. 8, 1963 R. L. AITKEN 3,106,292

' APPARATUS FOR SORTING TIMBER Filed April 13, 1961 4 Shee'cS-SheGt. 4

ROBERT LOUDON AIKEN- 3) W MVM United States Patent 3,106,292 APPARATUS FOR SORTING TIP/ BER Robert London Aitken, 50 Pall Mall, London SW. 1, England Filed Apr. 13, 1961, Ser. No. 102,879 9 Claims. (Cl. 20990) The present invention relates to apparatus for sorting timber according to length. When consignments of timber are received by timber merchants it is usual for them to consist of planks and the like, of varied lengths, and it is an object of this invention to provide a mechanical means for sorting these in accordance with their length.

It will be appreciated that if a timber plank is pushed lengthwise of a supporting table with the plank straddling a gap of progressively increasing width, there will come a point at which one end of the plank will fall off the table. If one end of the plank is maintained at a substantially constant longitudinal positionwith regard to one edge of the gap, the point at which the other end falls off the opposite edge of the table will be determined by its length.

The present invention provides an apparatus for sorting timber according to length which is based in its operation on this general idea. There are, however, difficulties to be overcome before a successful timbersorting apparatus can be constructed on these lines, and these problems are particularly concerned with the control of the planks after the one end has fallen from the supporting table.

According to the present invention an apparatus for sorting planks and the like according to length comprises a plank supporting table having a gap of progressively increasing width therein, means for progressing a plank along said table in a direction substantially parallel to one edge of said gap, so that one end of the plank will fall off the table at the other edge of said gap at a point, determined by its length, onto an auxiliary support and means for moving the plank transversely of the table in relation to the first edge of the gap while supported on said auxiliary support. The plank is preferably progressed along the table by means ofdogs on a pair of divergent drive chain-s, which are substantially parallel respectively to the general direction of the edges of the gap in the table.

The first edge of the supporting table has rollers or like low friction devices mounted therein at intervals so as to permit planks to be moved laterally of the table at those positions against very small accompanying resistance, and a force is applied by means of the drive chains for moving a plank at the low friction position laterally of the table, so as to move a plank supported on the auxiliary support away from the first edge of the gap and thus permit the other end of the plank to fall off through the gap and thus separate the plank from the supporting table. When the second end of the plank falls, it is preferably caught by a second auxiliary support parallel with, and at the same level as, the first auxiliary support. The plank-s are progressed by the chains along the auxiliary supports which are short in length and terminate in chutes or inclined roller trays.

The supporting table may comprise a pair of rails which are spaced by a gap of progressively increasing width, one of which rails lies lengthwise of the table in the general direction in which the planks are moved, so

' that one end of a plank is supported on that rail until it is moved laterally when the other end falls through the gap. As a preferred alternative, however, the second rail is formed in a number of sections parallel with the first rail, but stepped in relation to each other, so that the gap between the two rails increases in definite steps.

As an alternative the first rail may be comprised by one of the drive chains, which carries one end of the planks. In such case the end of the plank is carried on a roller, the axis of which extends longitudinally of the drive chain and is just forward of a drive dog carried by that chain.

The speeds or pitch of the drive chains are preferably so arranged that their velocity components parallel to the first edge of the gap are substantially equal, but where the angle of divergence of the sides of the gap is not too great the chains may be driven at equal velocity.

The dogs on the drive chain parallel to the first edge of the gap, whether this is constituted by a rail or by the drive chain itself, each carries a roller which engages the edge of a plank and is rotatable about a vertical axis, so as to present practically no restraining force against movement of a plank in a direction lateral to the first edge. The dogs on the other drive chain, however, are preferably plain or have a plain portion so that they may exert a frictional force on the planks in a direction away from the first edge to move the planlcs longitudinally. The value of the frictional force must be insumcient to move the planks longitudinally when they straddle the gap. On the other hand, when an end of a plank comes onto a roller portion of the first auxiliary support, the friction forces of both dogs and supports must be suffieient to move the plank longitudinally.

The invention is hereinafter described with reference to the accompanying drawings, wherein:

FIGURE 1 is a plan view of one form of length sorter.

FIGURE 2 is a side elevation of the apparatus of FIGURE 1.

FIGURE 3 is an isometric view of part of the apparatus'.

FIGURE 4 is an isometric view of an alternative form of apparatus.

FlGURE 5 is a detail of the chain conveyor used in the apparatus of FIGURE 4.

In FIGURES 1 and 2 a pack of timber, which is to be sorted according to length, is shown at 1. On the table 2 the planks 3 are pushed forward in the direction of the arrow by chains 5 and are sorted, according to length, by the action of the machine into packs 4 underneath and at spaced stations along the length of the table 2. The operation of the apparatus is best explained with reference to FIGURE 3.

The table 2 is comprised of a straight plane rail 6, including rollers 6a at each length sorting station. The rail 6 is also provided with a co-operating guide 7. A second rail in the form of a number of roller rail sections 8 progressively diverges in a series of steps from the plane rail 6, although the individual rail sections 8 are parallel with the rail 6. The conveyor chain 5 adjacent the rail 6 has dog-s 5b for engaging the planks. The dogs 5b which project from the side of the chain are roller dogs, whereas the conveyor chain 5 adjacent the rail sections 8 has plain dogs 5a, which likewise project inwardly from the side of the chain.

It will be seen in FIGURE 3 that plank 3a has just passed a position in which one end has fallen off a rail section 8. Up to this point, although the dog 5a has exerted a force tending to draw the plank 3a away from the guide 7, the supporting roller rail 8 has resisted such endwise movement of the plank. However, when an end of the plank 3a falls ed the rail section 8, it falls onto a roller 9 at the leading end of an auxiliary support rail 10, which terminates in a ramp portion 11 leading down to a pack collecting position. At the same time the upper end of'the now inclined plank is supported on a roller 6a, so that very little, if any, force is required to make the plank 3a move endwise. An endwise force is produced by the dog 5a and little resistance to endwise movement is given by the dog 512, so that the plank 3a moves and falls onto a second auxiliary support rail 16a, which likewise terminates in a ramp portion 11a. When the plank has fallen clear of the table 2 onto the auxiliary support, it is then progressed along until it reaches the ramp port-ions 11 and 11a; there it slides away down the ramps and separates from the drive dogs.

In the alternative construction shown in FIGURE 4 the general arrangement of the apparatus is the same as in FIGURES l and 2 and like parts have the same reference numerals applied to them.

in this construction the table is comprised of a stepped rail, composed of rail sections 8, and a conveyor chain 15, which support roller dogs 15b, in front of which are rollers 16, on which one end of the planks are carried.

In this construction, when the end of a plank falls oft a roller section 8, it falls onto an auxiliary support in the form of a roller rail 17, which is substantially parallel with the chain 5. As the plank is moved forward it tends to follow the roller rail 17 which diverges from the chain 15, and thus the plank moves endwise in relation to the roller 16 and roller dog 15b, and after a short further movement it falls onto a second auxiliary support in the form of a roller rail 17a, which is parallel with the roller rail 17. The roller rails 17 and 17a are slightly inclined to the horizontal so that the movement of a plank continues after it has fallen off the conveyor chain 15. The rails 17 and 17a lead into more steeply inclined roller tracks 18 and 18a which form storage trays in which the sorted planks accumulate until it is desired to build them up into sets.

I claim:

1. An apparatus for sorting planks and the :like according to length, comprising a plank supporting table having a gap of progressively increasing width therein so that when a plank is moved along the table in a direction parallel to one edge of the gap, one end of the plank will fall off the table at the other edge of the gap at a point determined by the length of the plank, auxiliary support means positioned below the level of said table and extending lengthwise of said table in said gap and proximate said other edge so as to receive the falling end of a plank, means adjacent the edges of said gap and said auxiliary support means for progressing a plank along said table in a direction substantially parallel to the edge of the gap and for moving the fallen end of a plank along said auxiliary suppont means lengthwise of said table at the same rate as the unfallen end is moved along said table parallel to the first edge, and means permitting said plank to move transversely of said table when supported upon said auxiliary support means to draw the unfallen end of the plank off said table.

2. An apparatus as claimed in claim 1, wherein one 4. edge of the gap is straight and the other edge of the gap is constituted by stepped lengths parallel to the first edge.

3. An apparatus as claimed in claim 2, wherein the means for progressing the plank along the table comprises a pair of chains, one chain of which is parallel to the one edge of the gap and the other chain of which diverges from it in the direction of travel, said other chain serving also to progress said plank lengthwise and transversely of said auxiliary support means.

4. An apparatus as claimed in claim 3, wherein the chain at the one edge of the gap carries drive dogs at spaced intervals, said dogs rotating about axes which are perpendicular to the plane in which the links of the chain move and constituting the means permitting transverse plank movement.

5. An apparatus as claimed in claim 4, wherein the edge of the table at said one edge of said gap is constituted by said chain, and said means permitting transverse plank movement comprises rollers which rotate about axes extending lengthwise of said chain and are positioned just forward of said dogs, so that a plank in contact with a dog is supported on a roller.

6. An apparatus as claimed in claim 5, wherein said auxiliary support is in the form of a roller rail and is divergent from said chain for being positioned to receive the end of the plank.

7. An apparatus as claimed in claim 6, wherein said auxiliary support further comprises a second roller rail positioned bet-ween said first roller rail and said chain and being parallel to said first roller rail.

8. An apparatus as claimed in claim 2, wherein said means permitting transverse plank movement comprise rollers provided at spaced intervals along the one edge of the gap, the said rollers being mounted to turn about axes extending along said edge.

9. An apparatus as claimed in claim 8, wherein said table comprises a rail extending along the one edge of the gap and said rollers are positioned in said rail at fixed intervals and said auxiliary support is positioned parallel with said rail, said auxiliary support including a roller at a position opposite to a roller in the rail at the one edge of the gap, so that as a plank falls onto the auxiliary support, it is supported at both ends on rollers so as to facilitate movement in a transverse direction relative to the table.

References Cited in the file of this patent UNITED STATES PATENTS 674,573 Dahl May 21, 1901 964,670 Moncreiife July 19, 1910 2,729,248 King Jan. 3, 1956 2,835,385 Eckart May 20, 1958 

1. AN APPARATUS FOR SORTING PLANKS AND THE LIKE ACCORDING TO LENGTH, COMPRISING A PLANK SUPPORTING TABLE HAVING A GAP OF PROGRESSIVELY INCREASING WIDTH THEREIN SO THAT WHEN A PLANK IS MOVED ALONG THE TABLE IN A DIRECTION PARALLEL TO ONE EDGE OF THE GAP, ONE END OF THE PLANK WILL FALL OFF THE TABLE AT THE OTHER EDGE OF THE GAP AT A POINT DETERMINED BY THE LENGTH OF THE PLANK, AUXILIARY SUPPORT MEANS POSITIONED BELOW THE LEVEL OF SAID TABLE AND EXTENDING LENGTHWISE OF SAID TABLE IN SAID GAP AND PROXIMATE SAID OTHER EDGE SO AS TO RECEIVE THE FALLING END OF A PLANK, MEANS ADJACENT THE EDGES OF SAID GAP AND SAID AUXILIARY SUPPORT MEANS FOR PROGRESSING A PLANK ALONG SAID TABLE IN A DIRECTION SUBSTANTIALLY PARALLEL TO THE EDGE OF THE GAP AND FOR MOVING THE FALLEN END OF A PLANK ALONG SAID AUXILIARY SUPPORT MEANS LENGTHWISE OF SAID TABLE AT THE SAME RATE AS THE UNFALLEN END IS MOVED ALONG SAID TABLE PARALLEL TO THE FIRST EDGE, AND MEANS PERMITTING SAID PLANK TO MOVE TRANSVERSELY OF SAID TABLE WHEN SUPPORTED UPON SAID AUXILIARY SUPPORT MEANS TO DRAW THE UNFALLEN END OF THE PLANK OFF SAID TABLE. 